1. Field of the Invention
The present invention generally relates to a disk cartridge, and more particularly to a technology for increasing the degree of freedom in the design of a disk drive apparatus and the positioning accuracy of a disk cartridge to the disk drive apparatus by forming four positioning portions on a shell of the disk cartridge.
2. Description of the Related Art
There are disk cartridges, each including a shell and a disk-shaped recording medium rotatably housed in the shell, in which the shell is provided with an opening portion formed thereon for exposing a part of the disk-shaped recording medium to the outside (see, for example, Patent Document 1).
When such disk cartridge is inserted into a disk drive apparatus from its insertion opening, the opening portion of the disk cartridge is opened, and then the disk-shaped recording medium is mounted on a disk table, which is to be inserted into the disk cartridge through the opening portion, to be rotated with the rotation of the disk table. When the disk-shaped recording medium is rotated, an optical pickup is activated, and the recording or the reproduction of an information signal to and from the disk-shaped recording medium is performed.
When the disk cartridge is inserted into the disk drive apparatus through the insertion opening, the shell of the disk cartridge is necessary to be located at a predetermined position and to be held at this position. A conventional disk cartridge have two positioning holes on the shell for the positioning of the disk cartridges. The positioning holes are, for example, formed apart on a right position and a left position of the end on the front side in the inserting direction of the disk cartridge into the insertion opening, that is, in a direction perpendicular to the thickness direction of the disk-shaped recording medium. One of the positioning holes is formed to be a circle, and the other of them is formed to be elongated in a right and left direction.
When such disk cartridge is inserted into the disk drive apparatus through the insertion opening and is moved horizontally, the inserted disk cartridge is led into a disk holder provided in the inside of the disk drive apparatus while the positional regulation of the disk cartridge in the right and left direction is performed. When the disk holder is then vertically moved to descend, two positioning pins provided in the inside of the disk drive apparatus are inserted into the respective positioning holes, and then the disk cartridge is located at a predetermined position.
[Patent Document 1] Japanese Patent Application Laid-Open Publication No. 2001-332058
As described above, in the conventional disk cartridge, the positioning relative to the disk drive apparatus is performed by means of the predetermined two positioning holes, and there is only one arrangement of the positioning pins to be formed in the disk drive apparatus, and consequently there is a problem that the designing of the disk drive apparatus is restricted to decrease the degree of freedom of the design thereof.
Moreover, when there is a displacement of the positions of the two positioning holes in the inserting direction, there is the possibility that a dimensional tolerance owing to the displacement is generated to generate a positional displacement of the disk cartridge owing to the dimensional tolerance.